a) Field of the Invention
The present invention is concerned with an improved bottle assembly for use to store and retail a liquid substance that generates gases when it is heated or contaminated. Such a liquid substance may be, for example, a fabric bleach like those presently available on the market.
More particularly, the invention is concerned with an improvement in the way such a bottle assembly is sealed to allow it to breath, i.e. to let any generated gas escape therefrom, while tightly retaining the liquid therein even if the bottle is tilted horizontally and the cap is partially unscrewed or removed as it may sometimes occur by accident.
b) Brief Description of the Prior Art
All the bottle assemblies that are presently in use for storing and retailing various bleach formulations like Javel water or any other simular liquid substances that may produce gases under certain conditions, comprise a bottle made of plastic material such as polyethylene that is compatible with the bleach and gases (O.sub.2, Cl.sub.2, . . . ) than may be generated by the bleach when heated or contaminated with heavy metals such as iron, chromium, nickel and copper. The bottle comprises a cylindrical neck having a threaded external surface and a circular upper edge of a given external diameter that defines a circular opening.
Each assembly also comprises a cap sized to fit onto the neck, the cap having a flat inside top wall that is circular in shape and a surrounding skirt that downwardly projects from the periphery of the top wall. This skirt has an internal surface that is so threaded as to make the cap screwable onto the neck of the bottle.
Each assembly further comprises a permanent seal in the form of a disk made of a material that is compatible to the bleach. This disk is sized to fit within the cap and is glued or otherwise fixed flat onto the flat inside top wall of this cap so as to be permanently held and to bear against the upper edge of the neck to seal the bottle when the cap is screwed onto the neck.
In accordance with the most common embodiment presently available in the market, the permanent seal glued within the cap which may have a thickness of 0.040 to 0.060 inch, is made of a porous plastic foam such as expanded polystyrene or expanded polyethylene whose porosity is selected to allow the gases generated within the bottle to pass therethrough, but not the liquid bleach.
This embodiment is efficient to let the bottle breath and thus prevent it from bulging and thus becoming unsaleable whenever subjected to heat or contamination. This embodiment however is not always efficient to prevent the bottle from leaking if it is inadvertently or accidentally knocked over. Indeed, the plastic cap and bottle manufacturing tolerances as well as the capping process during filling of the bottle prevent in some cases the permanent seal to bear equally against the upper edge of the neck all along the same. As a result, leaks may occur at the junction of the edge of the neck with the seal whenever the bottle is tilted horizontally and remains as such for a certain period of time.
To tentatively solve this problem, it has already been proposed to use a peelable seal in combination with the permanent seal in the above mentioned bottle assembly.
In accordance with this other embodiment that is also presently available in the market, the neck of the bottle is hermetically closed by a peelable seal of aluminum that must be removed by the customer when he or she opens the bottle for the very first time.
Of course, this other embodiment is efficient in that it does prevent the bottle from leaking if it is accidentally knocked down and the cap has been inadvertently partially unscrewed or removed. However this embodiment has three drawbacks.
The first one of these drawbacks is that induction heat is required to glue the aluminum seal onto the neck of the bottle. Because this aluminum seal is very thin and may easily fall out of the cap during the capping process, it is usually glued by a spot of wax onto the bottom surface of the permanent seal or laminated thereto with wax. After screwing of the cap onto the neck, induction heat is and must be applied to the neck and cap assembly to cause the aluminum seal whose bottom surface is covered by a layer of heat activated otherwise, to be glued onto the upper edge of the neck and simultaneously to be released from the permanent seal by melting of the spot of wax.
The second and most important drawback of this other embodiment is that the aluminum seal once it is glued onto the neck of the bottle, completely prevents the same from breathing, because of its hermetism to both liquids and gases. As a result, bulging may occur and causes some bottles to be unsaleable.
The third and last drawback of this other embodiment is that the aluminum seal once it is glued, is rather difficult to peal off, essentially because the seal itself is usually sized to fit exactly onto the neck of the bottle, thereby offering no means to grasp it with two fingers to peel it off, and the heat activated adhesive used to glue it is usually very strong. Therefore, the seal must be pierced and then teared off, with the inherent risk of splash and contact of the body with the bleach contained in the the bottle.
To solve the second and most important drawback listed hereinabove, it has already been proposed to make a plurality of very small perforations into the aluminum seal to let gases pass therethrough. This solution is efficient but does not solve the first and third drawbacks. Moreover, it has the drawback of letting some bleach or liquid soak the permanent membrane, which is often made of paperboard.
To solve the third drawback listed hereabove, it has also been proposed to provide the aluminum seal with an outwardly projecting grasping tab. Such a solution however substantially complicates the lining process, as a third protective seal must be intercalated between the permanent and peelable seals to protect the tab and prevent it from being glued. Moreover, this solution has the same drawback as mentioned above.